% \AddToCheckSum{309}
%
% \begin{warning}
% This code has not been well tested yet. The output routine of \LaTeX{} is
% very complicated, and unforseen problems might arise.
% \end{warning}
%
% \DescribeMacro\NextAux
% \DescribeMacro\DynamicAux
% \DescribeMacro\StaticAux
% The macro \cs\NextAux changes \cname{@auxout} to a new stream if one is
% available, and gives an error otherwise. The macro is implemented in
% dynamic and static ways which can be selected with \cs\DynamicAux and
% \cs\StaticAux\marg{number of streams}. The number of streams can be from 2
% to~16. The dynamic implementation is the default; I do not see much use
% for the static implementation at present. The \option{static} option is
% the equivalent of the declaration |\StaticAux{10}|. The \option{dynamic}
% selects the dynamic implementation.
%
% \cs\StaticAux can be invoked after \cs\DynamicAux, but not the other way
% around (at least, the streams allocated by \cs\StaticAux are not
% recovered). Macros which use \cs\NextAux do not have to know whether the
% implementation is static or dynamic.
%
% \subsubsection{Wheels}
%
% The output streams are manipulated with the help of a data structure I call a
% \word{wheel}.
%
% A \term{wheel} has 0 or more \term{spokes} and can be \term{rolled}. Each
% spoke is a \TeX{} token, probably a control sequence name, and has an
% internal name. You can access the spoke at the 12 o'clock or ``top''
% position of a wheel. In computerese, a wheel is a circularly linked list of
% tokens, and the operation of rolling moves a pointer along it in a certain
% direction by one element.
%
% Wheels and operations on wheels are local.
%
% \DescribeMacro\InitWheel
% \DescribeMacro\DefWheel
% You make a wheel either with \cs\InitWheel\marg{\\csname}, which makes
% \meta{\\csname} a wheel with no spokes, or
% \cs\DefWheel\marg{\\csname}\marg{spokes}, which makes a wheel with
% \meta{spokes} for spokes. The first spoke in \meta{spokes} is the top, the
% second will be top after one roll, and the first will be top again after
% $n$ rolls, if there are $n$ spokes.
%
% \DescribeMacro\Roll
% \DescribeMacro\Top
% \DescribeMacro\AddSpokes
% Wheels are rolled by \cs\Roll\marg{wheel}. Spokes can be added to a
% wheel with \cs\AddSpokes\marg{wheel}\marg{spokes}. When $n$ spokes are
% added, the previous top will be at the top after $n$ rolls.
% \cs\Top\marg{wheel} expands eventually to the top spoke, which then can
% further expand, and so on.
%
% \DescribeMacro\IfTop
% \cs\IfTop\marg{wheel}\marg{spoke}\marg{true clause}\marg{false clause}
% compares the top of \meta{wheel} with \meta{spoke} using \cname{ifx}, and
% executes either \meta{true clause} or \meta{false clause} as appropriate.
% (The \package{newclude} package doesn't actually use this command; it's
% provided to ``round out'' the wheel data structure.)
%
% \caveat{Don't put more than one token as the second argument to \cs\IfTop.}
%
% \subsubsection{Preliminaries}
%
% We require the \package{afterpage} package. The intuitive justification is
% that \cs\write{}s are delayed until the current page is shipped out. We need
% to keep an output stream open until its last \cs\write has been actually
% handled; after that, the stream can be made available again.
% \begin{macrocode}
\RequirePackage{afterpage}
% \end{macrocode}
%
% \begin{macro}{\nc@aux@wheel}
% We use the wheel structure to handle both the static case and the dynamic
% case. The spokes of the wheel are macros |\nc@auxout@|\meta{n}. Their
% first-level expansion is \meta{n}, a positive integer from 0 to~15. Each
% spoke has two corresponding macros. |\nc@auxout@|\meta{n}|@stream| is a
% stream name allocated by \cs\newwrite. |\nc@auxout@|\meta{n}|@inuse| is a
% global boolean which is |true| iff the corresponding stream is currently in
% use.
% \begin{macrocode}
\InitWheel\nc@aux@wheel
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\nc@count}
% We need an internal counter. Notice that the stream numbers used in the
% auxwheel start at 0, so the stream associated with with the numeral 4 is
% the fifth stream.
% \begin{macrocode}
\newcounter{nc@count}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\nc@aux@wheel@size}
% \cname{nc@aux@wheel@size} is a pseudo-counter that holds the present size
% of the aux wheel. In the static case it never changes and is set only for
% consistency.
% \begin{macrocode}
\ReserveCS\nc@aux@wheel@size
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\NextAux}
% \mbox{}
% \begin{macrocode}
\ReserveCS\NextAux
% \end{macrocode}
% \end{macro}
%
% The kernel allocates two streams for the include system, \cname{@mainaux} and
% \cname{@partaux}. The auxwheel is initialized with these two streams. The
% first, corresponding to the principle source, is always marked in use.
%
% \todo{Reserve the stream names.}
% \begin{macrocode}
\newboolean{@nc@auxout@1@inuse@}
\ReserveName{nc@auxout@1}
\NewName*{nc@auxout@1} {} {1}
\ReserveName{nc@auxout@1@stream}
\expandafter\let\csname nc@auxout@1@stream\endcsname\@partaux
% \end{macrocode}
%
% \begin{macro}{\nc@init@aux@wheel}
% We initialize the wheel with the first spoke.
% \begin{macrocode}
\newcommand\nc@init@aux@wheel {%
\EExpand\csname nc@auxout@1\endcsname\In {%
\AddSpokes\nc@aux@wheel##1%
}
}
% \end{macrocode}
% \end{macro}
%
% \subsubsection{Static allocation}
%
% \begin{macro}{\StaticAux}
% nonpositive numbers are treated the same as~1. \todo{bounds check; the
% counter's max should be one less than the number, since we have stream 0.}
% \begin{macrocode}
\newcommand\StaticAux [1] {%
\def\nc@aux@wheel@size {#1}
\setcounter{nc@count}{2}
\nc@init@aux@wheel
\@whilenum \value{nc@count} <= \nc@aux@wheel@size
\do {%
% \end{macrocode}
% First define the macros that make up the wheel itself to be their spoke
% numbers.
% \begin{macrocode}
\eExpand*\thenc@count\In {%
\NewName*{nc@auxout@\thenc@count} {} {%
##1%
}%
}
% \end{macrocode}
% Next allocate the corresponding stream.
% \begin{macrocode}
\EExpand\csname nc@auxout@\thenc@count@stream\endcsname\In {%
\@nameuse{newwrite}##1%
}
% \end{macrocode}
% Next create the corresponding flag (they start |false|).
% \begin{macrocode}
\provideboolean{@nc@auxout@\thenc@count @inuse@}
% \end{macrocode}
% Now add the spoke itself.
% \begin{macrocode}
\EExpand\csname nc@auxout@\thenc@count\endcsname\In {%
\ReserveCS#1%
\AddSpokes\nc@aux@wheel##1%
}
\stepcounter{nc@count}
}
\def\NextAux {%
\Roll\nc@aux@wheel
\@nameuse{if@nc@auxout@\Top\nc@aux@wheel @inuse@}%
\MonsterError{newclude} {%
You can't nest \protect\include this deeply!%
}%
\else
\Elet\@auxout\csname nc@auxout@\Top\nc@aux@wheel @stream\endcsname
\fi
}%
}
% \end{macrocode}
% \end{macro}
%
% \subsubsection{Dynamic allocation}
%
% \begin{macro}{\DynamicAux}
% \begin{macro}{\nc@addnewauxstream}
% \mbox{}
% \begin{macrocode}
\newcommand\DynamicAux {%
\def\nc@aux@wheel@size {1}
\nc@init@aux@wheel
\def\NextAux {%
\Roll\nc@aux@wheel
\@nameuse{if@nc@auxout@\Top\nc@aux@wheel @inuse@}%
\nc@addnewauxstream
\fi
% \end{macrocode}
% Either the top spoke was not in use, or we have added a fresh spoke at the
% top -- so the top spoke represents what we want.
% \begin{macrocode}
\Elet\@auxout\csname nc@auxout@\Top\nc@aux@wheel @stream\endcsname
\typeout{NextAux has just set auxout to stream
\the\csname nc@auxout@\Top\nc@aux@wheel @stream\endcsname.
We are using spoke number
\csname nc@auxout@\Top\nc@aux@wheel\endcsname.}
}%
}
% \end{macrocode}
% It works out that the new spoke should have a spoke number one greater than
% the current wheel size. We use the |nc@count| counter to find this number.
% \begin{macrocode}
\newcommand\nc@addnewauxstream {%
\setcounter{nc@count}{\nc@aux@wheel@size}%
\stepcounter{nc@count}%
\typeout{Allocating another spoke (spoke number \thenc@count)}%
% \end{macrocode}
% First we add the spoke itself, then initialize the corresponding objects.
% \begin{macrocode}
\EExpand*\csname nc@auxout@\thenc@count\endcsname\In {%
\AddSpokes\nc@aux@wheel##1%
}%
\EExpand*\thenc@count\In {%
\DefName*{nc@auxout@##1} {} {##1}%
\provideboolean{@nc@auxout@##1@inuse@}%
\def\nc@aux@wheel@size {##1}%
\EExpand*\csname nc@auxout@##1@stream\endcsname\In {%
\@nameuse{newwrite}####1%
}%
}%
}
\DynamicAux
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsubsection{Including}
%
% \begin{macro}{\nc@include}
% The only way I see how to set the |inuse| flag to |false| at the proper
% time is to use the \package{afterpage} package. What I would really like
% is to \cs\write something with side effects.
% \begin{macrocode}
\newcommand\nc@include [2][] {%
\if@filesw
\immediate\write\@mainaux{\string\@input{#2.aux}}%
\fi
\@tempswatrue
\if@partsw
\@tempswafalse
\edef\reserved@b{#2}%
\@for\reserved@a:=\@partlist\do
{\ifx\reserved@a\reserved@b\@tempswatrue\fi}%
\fi
\if@tempswa
\stepcounter{IncludeDepth}%
% \end{macrocode}
% \cname{nc@t@c} is going to preserve the current \ext{aux} stream number to
% restore \cname{@auxout}, in case there is a nested \cs\include.
% \begin{macrocode}
\edef\nc@t@c {%
\the\@auxout
}%
\if@filesw
\NextAux
\openout\@auxout #2.aux
\write\@auxout{\relax}%
\expandafter\global
\csname @nc@auxout@\Top\nc@aux@wheel @inuse@true\endcsname
% \end{macrocode}
% \begin{macro}{\nc@include@finish@<N>}
% The next line defines the macro |\nc@include@finish@|\meta{n} to close the
% output stream that is presently open. We have an interesting task here of
% getting certain unique information to macros after the \cname{@input} when we
% might end up recursing during the \cname{@input}. To do this, we immediately
% expand the variables we need and store them in a macro which will \emph{not}
% be altered by a recursion of \cs\include. We have set up the |IncludeDepth|
% counter to allow us to define such a macro, which is unique to \emph{this}
% instance of \cs\include.
%
% \begin{warning}
% The macro names |\nc@include@finish@|\meta{n} where \meta{n} is an
% integer are overwritten, that is, they are not allocated in a safe way.
% \end{warning}
%
% The following lines are intended to make this definition, where |<D>|
% represents the current value of |IncludeDepth|, |<P>| represents the spoke
% number of the current top of \cname{nc@aux@wheel}, and |<S>| represents the
% stream number for the current part, i.e., the current value of
% \cname{@auxout}, and |<X>| represents the stream number that was current
% before \cs\include got called (this is saved in \cname{nc@t@c}).
% \begin{codeexample}
% \def\nc@include@finish@<D> {%
% \closeout<S>%
% \global\chardef\@auxout=<X>%
% \afterpage{\global\@nc@auxout@<P>@inuse@false}
% }
% \end{codeexample}
% \begin{macrocode}
\EExpand\theIncludeDepth\In {% ##1
\EExpand\the\@auxout\In {% ####1
\DefName{nc@include@finish@##1} {} {%
\closeout####1%
\global\chardef\@auxout=\nc@t@c
\typeout{Restored auxout to stream number
\nc@t@c \space (old: \the\@auxout)}
\typeout{executing afterpage}%
\EExpand\csname @nc@auxout@\Top\nc@aux@wheel
@inuse@false\endcsname\In {% ########1
\afterpage{%
\typeout{Finishing. auxout is now \the\@auxout; current spoke
is \csname nc@auxout@\Top\nc@aux@wheel\endcsname\space
with stream number
\the\csname nc@auxout@\Top\nc@aux@wheel @stream\endcsname
}%
\global########1%
}% Afterpage
}% EExpand
}% DefName
}}% EExpand
\fi % \if@filesw
\nc@t@b % surround the \include with something
% \end{macrocode}
% Now execute the text of the optional argument to \cs\include. Notice that if
% we change to a new \ext{aux} file, we should do it before the optional
% argument. This is important so that sectioning commands will appear in the
% right order. If the sectioning command were to write to \cname{@mainaux},
% then it would come \emph{after} the whole included \ext{aux} file, instead of
% before it.
% \begin{macrocode}
#1%
\@input@{#2.tex}%
\@writeckpt{#2}%
\if@filesw
\csname nc@include@finish@\theIncludeDepth\endcsname
\fi
\nc@t@b % surround the \include with something
% \end{macrocode}
% We mustn't restore the counter before we have finished using it.
% \begin{macrocode}
\addtocounter{IncludeDepth}{\m@ne}%
% \end{macrocode}
% If the file is excluded by the \cs\includeonly command, we don't load it and
% execute the file's checkpoint instead.
% \begin{macrocode}
\else
\@nameuse{cp@#2}%
\fi
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsubsection{Checkpoints}
%
% \begin{macro}{\@writeckpt}
% \begin{macro}{\@wckptelt}
% We must redefine the macros which write the checkpoints. \cname{@auxout}
% is substituted for \cname{@partaux}; I think this change should be in the
% kernel anyway! And we remove the \cs\immediate{}s.
% \begin{macrocode}
\defcommand\@writeckpt [1] {%
\if@filesw
\write\@auxout{\string\@setckpt{#1}\@charlb}%
\begingroup
\let\@elt\@wckptelt
\cl@@ckpt
\endgroup
\write\@auxout{\@charrb}%
\fi
}
\defcommand\@wckptelt [1] {%
\protected@write\@auxout{}{\string\setcounter{#1}{\the\@nameuse{c@#1}}}%
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsubsection{Wheels}
%
% \begin{macro}{\InitWheel}
% \begin{macro}{\Roll}
% \begin{macro}{\IfTop}
% \begin{macro}{\Top}
% \begin{macro}{\AddSpokes}
% A wheel is implemented as a macro. The tokens of its first-level expansion
% are the spokes, the top being the first.
% \begin{macrocode}
\newcommand\InitWheel [1] {% args: wheel
\InitCS#1%
}
\newcommand\Roll [1] {% args: wheel
\edef #1{%
\expandafter\nc@roll #1\nc@llor
}%
}
\ReserveCS\nc@llor
\NewNameDef{nc@roll} {#1\nc@llor} {%
\@cdr#1\@nil\@car#1\@nil
}
\newcommand\Top [1] {% args: wheel
\E@car #1\@nil
}
\newcommand\IfTop [4] {% args: wheel token true false
\EExpand#1\In {%
\edef\nc@t@b {%
\expandafter\noexpand\@car##1\@nil
}%
}%
% \end{macrocode}
% At this point, the first-level expansion of \cname{nc@t@b} is a single token,
% the top of the wheel. We \cs\let \cname{nc@t@a} to this token.
% \begin{macrocode}
\Elet\nc@t@a\nc@t@b
\let\nc@t@b #2%
\ifx\nc@t@a\nc@t@b
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi
}
\newcommand\AddSpokes [2] {% args: wheel spokes
\EExpand#1\In {%
\def #1{#2##1}%
}%
}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}